What is lymph? Describe its composition

 

Q:  What is lymph? Describe its composition. How it is returned to blood. Also mention the function of lymphatic system. Or give detailed account of lymphatic system and functions it performs.
 

LYMPH

       Some of the fluid of blood is constantly passing through the capillary walls and entering the spaces between the cell. Now it is called tissue fluid or lymph. Blood cells expert the white blood cells, are not allowed to pass through the capillary walls. Therefore composition of tissue fluid (lymph) and blood differs primarily in the sense that the former lack red blood cells, most of the white blood cells and some kinds of proteins. Tissue fluid bathes the cells then some of it may reenter the blood stream directly through the capillaries, but most of the fluid (lymph) passes into a separate network of vessels that constitute the lymphatic system. The fluid travelling through the lymph vessels is called lymph. Lymph from the intercellular spaces is largely collected by the microscopic lymph capillaries called lacteals. The lacteals join to make large vessels resembling the veins.

 

The human lymphatic system

 

FLOW OF LYMPH

               The flow of lymph in the lymph vessels is brought about by the contraction and relaxation of the skeletal muscles and the breathing movements. The direction of flow is towards the main trunks but the lymphatic system is not of closed type but the lymph capillaries (lacteals) end blindly. The main vessels have to prevent backward flow.

LYMPH NODES

         At many points of the body where the smaller lymph vessels join to form the larger ones, there are special aggregation of cells called lymph nodes. The lymph nodes are present at various places in the body, such as in body defences against disease. During infection they swell as they remove bacteria and other foreign bodies.

 

FUNCTIONSOF LYMPHATIC SYSTEM

1-             Large protein molecules and fats are transported and returned to blood stream.

2-             The lymph nodes produce lymphocytes and antibodies.

3-              The lymph nodes serve to remove microorganisms and other foreign bodies, and broken cancer cells.